1. Field of the Invention
This invention relates generally to means for fastening a strip element relative to the edge of a panel and support structure adjacent the panel and, more particularly, to resilient fasteners for mounting a shaped molding across the gap between the peripheral edge of a window panel and bodywork supporting the panel in an automotive vehicle.
2. Description of the Prior Art
In automotive vehicles, the fixed windows, such as the windshield and rear window, are typically held within a fillister formed in the bodywork defining the window opening by means of an adhesive. The fillister includes a pair of oblique sides, a first of which is generally parallel to the edge of the panel and a second of which is generally parallel to the inside major surface of the panel. The adhesive is typically applied in a continuous beading around the periphery of the inside surface of the panel and the panel, with the adhesive so applied, is pressed against the fillister so that the adhesive is squeezed between the panel and the second side of the fillister.
When the window panel is mounted in this manner, a gap remains around the periphery of the panel between the edge of the panel and the first side of the fillister. This gap is typically concealed by an embellishing element, which in most cases is formed as a metal molding strip shaped to match the periphery of the opening.
To provide the window, molding, and surrounding bodywork with an aesthetically neat appearance, it is important that the molding be properly positioned relative to window and fillister around the entire periphery of the window. It is also important that the molding be firmly retained in position to prevent the inadvertent loosening or detachment of the molding during the life of the vehicle.
The customary way of mounting the molding across the gap has been to weld a plurality of headed studs in the fillister at spaced positions around the periphery of the opening. Specially designed molding clips are then anchored to these studs. The clips typically include members that protrude from the gap and engage within the molding to hold the molding in position over the gap. Examples of stud engaging fastening clips of this type are shown in U.S. Pat. No. 3,631,569 and British Pat. No. 1,292,103.
The primary drawback of the stud fastening technique is its relative inconvenience. The welding of the studs within the fillister takes considerable time and thus slows the vehicle assembly process. The welding operation must also be carefully controlled in terms of stud height and alignment if the clips and moldings are to fit properly. Further, the welding operation stresses the metal of the fillister and often leaves a carbon smut deposit at the base of the stud, thus hindering effective paint adhesion to the fillister adjacent the stud base and presenting a condition that is conductive to premature rusting of the bodywork adjacent the studs from moisture that may leak into the area.
A number of proposals have been made for fasteners that are capable of attaching a molding across the gap between a mounted window panel and fillister without the need for welded studs. These stud-less fasteners have typically been formed as molded plastic units which include members that embrace the edge of the window panel to retain the fastener in position in the fillister and members that protrude from the gap and snap within or otherwise engage the molding to retain the molding in position across the gap. Examples of such fasteners are shown in U.S. Pat. No. 3,611,663 and in British Pat. Nos. 1,232,344 and 1,237,500.
Prior stud-less fasteners of the above type, though generally recognized as effective in simplifying the vehicle assembly process, have had a number of problems that have militated against their widespread acceptance and use by vehicle manufacturers. One problem relates to their inability to accommodate the manufacturing and assembly tolerances that normally exist between the window panel and fillister in the vehicles. Some prior stud-less fasteners are capable of accommodating tolerances in one direction; namely, in the width of the gap between the edge of the window panel and the first side of the fillister.
Typically, members in such fasteners that embrace the edge of the panel are formed as upwardly directed, resilient wings that can be downwardly flexed to fit within a gap having a width anywhere within a certain range. However, most of these fasteners have difficulty accommodating tolerances in the other, transverse direction; namely, in the spacing between the inside surface of the window panel and the second side of the fillister. This problem results because the prior fasteners tend to position themselves in reference to the edge of the mounted panel. If, for example, the spacing between the mounted panel and the second side of the fillister is too large, the fastener protrudes too far from the fillister and the molding in turn, is bowed away from the body in the vicinity of the fastener. If, on the other hand, the spacing is too small, the fastener is set back too far within the fillister and the molding, in turn, either is bowed inwardly in the vicinity of the fastener or is prevented from engaging the fastener at all. The appearance of the molding is thus adversely affected.
Another problem with prior stud-less fasteners is that they have had difficulty meeting automotive manufacturers' specifications with respect to the amount of pulling force that can be applied to the molding prior to detachment of the molding. In some cases, the members on the fasteners that engage and retain the molding are so flexible that the molding can easily be pulled from the members when force is applied to the molding, particularly when the side of the molding that overlaps the window panel is pulled away from the panel. In other cases, the retaining members adequately hold the molding, but the fasteners themselves are such that, when the molding is pulled away from the window panel, the entire fastener is easily pulled from the gap. While it is desirable that the molding be detachable from the fasteners and the fasteners be removable from the gap in the event repair or replacement of the molding or window panel is required, the fasteners should not permit the molding to be detached inadvertently such as, for example, when an object is forced between the molding and panel.